Hi,
I just selected a Canadian merchant from a random search and this is what is on their shipping info, so unless that lil ol' snowsuit is terribly expensive (like over $2,000

), then you are not required to give out that info:
Tax ID Number or SSN
For orders being shipped into the USA,
US Customs declarations now require an SSN (social security number) or IRS ID number for orders over $2000 US.
If your order is under that amount, you do not need to provide either number when ordering. http://www.hortico.com/ordering/orderhelp.asp